Semiconductor, solar, or other types of workpieces may be processed within ion implantation systems. Some ion implantation systems may comprise an ion source, extraction electrodes, a mass analyzer, a collimating magnet, one or more acceleration or deceleration stages and a process chamber that holds the workpiece. Throughout this disclosure, the term “housing” is used to refer to any chamber or other enclosure through which an ion beam passes. Thus, the housings include, for example, the deceleration stages, the mass analyzer, the collimating magnet and the process chamber. It is common for components disposed within these housings, such as the interior walls, electrodes, insulators and other equipment to show signs of deterioration or become coated. This may be due to the deposition of ions or other materials on these components. For example, metallic material, such as tungsten, may be etched from within the ion source, and become deposited on a bushing or other insulating component in another region of the ion implantation system. For example, components, such as bushings, cables, electrodes, lenses, and interior walls may become coated. These coatings may become deleterious. For example, a coating may be more conductive than the underlying component, thereby creating a conductive path where none previously existed.
Therefore, after a period of ion implantation system operation, this coating becomes deleterious, and must be removed. This is a common practice in this field and these coatings may be removed during a process known as a preventative maintenance (or “PM”) cycle. During the preventative maintenance cycle, each component may be cleaned in order to remove the coating, or replaced if the damage is too significant. This process may be quite time consuming, as each component must be inspected and cleaned. This may result in unacceptable periods of time where the housings are inactive, which results in reduced throughput. In addition, the frequency of this preventative maintenance may be unacceptable. For example, in some embodiments, where BF3 is used as a feed gas, preventative maintenance may need to be performed after only 75 hours of continuous operation.
In some embodiments, a co-gas, such as Xe:H2 is also fed into the ion source. This co-gas disrupts the halogen cycle, greatly reducing the production of volatile tungsten compounds. However, the use of a co-gas may be expensive and reduces the concentration of feed gas. This approach also requires the use of one of the valuable bottle positions in the tool. Therefore, an improved system and method of extending the life of components, and particularly insulating components, disposed within a housing would be beneficial.